China's foreign ministry says it has no information on North Korean leader Kim Jong-un, amid conflicting reports and speculation about his whereabouts and medical condition.

Foreign ministry spokesman Geng Shuang made the comment during a daily briefing after being asked about reports of a Chinese delegation, including medical experts, being dispatched to North Korea, and whether they were sent to assist Mr Kim or help the country deal with Covid-19.

Sources said a Chinese team was dispatched to North Korea last Thursday to advise on Mr Kim, though it was not clear what this meant about the North Korean leader's health.

Mr Kim's prolonged public absence has led to rumours but there is a basic, unanswered question - are the rumours even true?

The state of Mr Kim's health matters because it could affect the stability of the dynastic government in Pyongyang and the security of nuclear weapons the nation has repeatedly threatened to use on its neighbours and the United States.

It is a problem outside nations have faced for decades - gathering intelligence on perhaps the world's most secretive country is incredibly difficult. And there is probably nothing North Korea guards more closely than information on Mr Kim's health, which is only shared among a small number of the elite, including his powerful sister, Kim Yo-jong.

A South Korean official has said that Kim Jong-un's absence from the public eye suggests "he has not been working as normal", amid mounting speculation that the North Korean leader has fallen ill.

Although the South Korean government has dismissed rumours regarding Mr Kim's health, insisting that he is "alive and well", questions persist.

Yoon Sang-hyun, chairman of the foreign and unification committee in South Korea's National Assembly, told a gathering of experts yesterday the leader's prolonged absence indicated "he has not been working as normal".

"There has not been any report showing he's making policy decisions as usual since 11 April, which leads us to assume that he is either sick or being isolated because of coronavirus concerns," Mr Yoon said.

However unfounded the fears may be, some experts say South Korea, as well as its regional neighbours and ally the United States, must begin preparing for the high-level instability which could come if Mr Kim is sidelined by health problems or even dies. That could include North Korean refugees flooding South Korea or China, or military hard-liners letting loose nuclear weapons.

While those are worst-case scenarios, planning for them is crucial because nobody knows for sure what is happening inside North Korea, said Nam Sung-wook, a North Korea expert at Seoul's Korea University who termed the situation the "Achilles heel of international politics in north-east Asia.

Mr Kim is overweight, reportedly smokes heavily and has other health problems. He was last seen in public on April 11.